Sit-up exercise bar



FIG. 1 is a perspective view of a "sit-up exercise bar" showing my newdesign;

FIG. 2 is a left-end elevational view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof.

The ornamental design for a "sit-up exercise bar", as shown anddescribed.